Conventionally, a wiper device is known in which a metal frame pipe serving as a frame member is swaged in a state where a coupling portion, which projects from a pivot holder, is inserted in the metal frame pipe, to couple the pivot holder to the metal frame pipe (see, for example, Patent Documents 1 and 2). The pivot holders described in those documents are formed by performing die-casting on aluminum.
Further, to meet the recent demands for weight reduction in a vehicle body, a plastic pivot holder has been proposed (see, for example, Patent Document 3). The plastic pivot holder described in this document is formed integrally with an elongated metal frame pipe on an end portion of the frame pipe so that the pivot holder can be coupled to the metal frame pipe. To form the plastic pivot holder integrally with the metal frame pipe, it is necessary to set the metal frame pipe in a metal mold beforehand.